It reads prettily (though I found the pull-quotes on facing pages distracting), but it feels disconnected -- both as a whole, and also disconnected from my experiences (albeit second-hand) of severe, chronic depression.
The opening vignettes are about grief, and leaving aside the fact that the formatting often makes it difficult to distinguish blockquote from maintext, I'm really not interested in pages about grief as a way to ramp into, "And some people have a biological disposition to have much greater difficulty recovering from emotional hurt" -- though I recognize that that's probably a helpful framing for a lot of people.
The author states that "Depression [...] has its origins in the wounds of our childhood that we have never wanted to own or to name" (15). The chapter makes sense, and I appreciate that it's immediately followed by a chapter titled "Chemical Changes in the Body," though that chapter basically doesn't say anything beyond "In many ways, biology and psychology are ONE, because the human being is ONE. Some people have a biological predisposition to depression inherited from their parents" (27), which is fine, but I would like a little bit more (and yes, I feel the irony, given that I've found the ~medical chapters in recent books I've read a bit excessive).
I'm not really sure what to say about the rest of the book. The chapter titles say most of it for me:
5. The Winters of Life Prepare the Way for Springtime
6. You Are Part of a Beautiful Universe
7. The Deepest Person Within Each One of Us
8. Struggling Against the Powers of Death
9. Knowing How to Rest
10. Going Down Into the Darkness
11. Depression: A Crisis Which Can Set Us Free
12. Getting Out of Depression
It reads prettily, but I come away from it with a sense of, "Depression is a dark season, and if you love someone who's depressed, love them as they are and let them emerge at their own pace, and if you are depressed, recognize that you are not alone, help is out there, and as you find trustworthy people to listen to you and possibly medication, as you learn how to recognize the deepest self within you, who is connected to the beautiful universe, as you find ways to be strengthened and uplifted by the beauty of nature, as you move through the darkness to emerge on the other side, you will find healing, and you will also have increased empathy for other people who are in pain." None of which is necessarily untrue, but.. I think it's partly the sense I get of "Depression is a dark season -- which can/will pass." The author does mention in the last chapter that some people may have to continue to take medication, may have to be hospitalized again, etc., but I still felt like the norm was that while you might always be somewhat fragile, severe bouts of depression are distinct phases -- which feels to me like an oversimplification of many people's experiences of chronic, severe depression (which may not be the kind of depression Vanier particularly has in mind, of course, which is its own problem).